This invention relates to a manually operated dispensing pump for mixing and simultaneously delivering two separate materials, preferably two fluids. In particular, the invention relates to such a dispensing pump in which the proportions of a first fluid to a second material to be dispensed are such that a relatively large amount of the first fluid is mixed with a relatively small amount of the second material. Commonly, the second material is a concentrate, active ingredient, or activating substance that is mixed in relatively small quantities with the first fluid, which may be a liquid diluant, carrier, or substance requiring activation just prior to use.
The art relating to manually activated pumps for spraying two liquids simultaneously is crowded. Commonly, as in Park and Corba, U.S. Pat. No. 5,472,119, the pumps are intended to be used with dual bottles of very similar construction. See also Cataneo et al., U.S. Pat. No. 5,385,270; Lawrence et al., U.S. Pat. No. 5,009,342; Avoy, U.S. Pat. No. 4,902,281; Skorka et al., U.S. Pat. No. 4,826,048; Castner et al., U.S. Pat. No. 3,760,986; Proctor, U.S. Pat. No. 5,332,157; Wilder, U.S. Pat. No. 5,339,990; and Fiedler et al., U.S. Pat. No. 4,949,874. The disclosures of these patents and of all other publications referred to herein are incorporated by reference as if fully set forth herein.
Some of the prior art devices employ entirely separate and parallel pumping systems, one for each liquid container, with the output of the pumping systems being mixed at or just prior to a nozzle (see Skorka et al. and Barriac et al., U.S. Pat. No. 5,535,950 at FIG. 9, as examples). Other art employs separate dip tubes or other liquid transfer means, each drawing from separate bottles, with the liquids to be dispensed drawn by a single piston to a mixing chamber prior to entering the piston for ultimate expulsion through a nozzle. See, for example, Maas et al., U.S. Pat. No. 5,626,259; Cataneo et al., U.S. Pat. No. 5,385,270; Lawrence et al., U.S. Pat. No. 5,009,342; and Park et al., U.S. Pat. No. 5,472,119.
Procter, U.S. Pat. No. 5,332,157, shows a cylinder and piston device in which liquid is led via liquid transfer means to valved openings in the face of a piston. The head room within the cylinder above the piston serves as a mixing chamber. Similarly, O'Neill, U.S. Pat. No. 5,562,250, shows a single cylinder and piston arrangement, with the space in the cylinder above the piston serving as a mixing chamber. In O'Neill, dip tubes descending to the compartments of a multiple-compartment container communicate directly with openings in the cylinder.
The relative amounts of liquid pumped from different compartments is controlled most commonly by constricting or selecting the relative sizes of the liquid flow paths at some point between the containers and the place where they are mixed before being dispensed. See O'Neill, U.S. Pat. No. 5,562,250, Vierkotter, U.S. Pat. No. 4,355,739, Metzler, III, U.S. Pat. No. 3,786,963, among others.
Devices with dual pump cylinders, such as Barriac et al., U.S. Pat. No. 5,535,950, clearly could achieve relative metering of materials by selection of the relative displacement volumes of each of the two pumping mechanisms. A device acknowledged to be prior art and believed to be assigned to Calmar, Inc., of City of Industry, Calif., employs two, separate pistons of differing sizes. The smaller piston is directly mounted as an axial extension of the larger piston, with valving such that the small piston always draws liquid from the container attached to it in an amount that is in a fixed relation to that drawn by the larger piston from the container attached to the larger piston. The liquid drawn into the smaller piston via a dip tube communicating with a secondary container is discharged directly into the head space above the larger piston, which serves as a mixing chamber.
Several important matters are not well addressed by the art. For example, especially if a secondary container's contents are a concentrate, dip tubes and other extensive fluid transfer means may require that inconvenient amounts of the concentrate be expended simply to prime the pump or otherwise fill the system. The art does not provide a manually operated dispensing pump designed to pump fluid from a primary container and combine it with contents drawn from a secondary container where the secondary container's contents are delivered to a mixing chamber without having to pass through an intervening dip tube or comparable, extensive fluid transfer means.
Furthermore, the art does not show such a device that also provides for the convenient replacement of one secondary container by another secondary container, without disturbing the primary container. A replaceable secondary container would allow convenient recharging of the device or the exchange of one secondary ingredient for another.
In addition, much of the art shows multiple containers to be either grouped as subdivided parts of a unitarily formed bottle or to be a smaller reservoir inserted within a larger bottle. In the latter arrangement, the smaller reservoir is bathed on its outside by the liquid contained by the larger bottle while it holds on its inside its own contents, and the former arrangement requires at least a common wall. In either case, the second reservoir must be made of a material that can successfully contain one of the two materials to be co-dispensed while it can also resist infiltration by the other material.
However, one of the advantages of dual dispensing is the opportunity to dispense essentially incompatible materials that are mixed in the dispensing pump and immediately applied. Such incompatible materials may well have different containment requirements, making it desirable that the two reservoirs be held physically separate from each other. The art provides no convenient means for providing for such separation without the need for dip tubes or other extensive fluid transfer means for each reservoir.